Having my father kill himself would completely crush me no matter my age. It would actually be worse if I was older, as that would enable me to reflect on why he would do it, and constantly contemplate what could have made his life so horrible that he'd leave it (and me) behind. I hope you'll consider this when your daughter turns 18. Losing her dad to suicide won't be any less of a torment just because she's older.
But to answer the question in topic: Life is what keeps me from suicide. The summer grass, the night sky, the ocean waves, the wonderful music, the arts, the unsolved mysteries. I could never let go of what might be my only chance to experience as much as possible of this wondrous world. It can be cruel and gruesome, but it can also be so amazing. I keep thinking that better days are lurking just around the riverbend. In a way I could also say that hope is what keeps me going.